Yellowfin Tuna?

From a dock on Pilot Island with frozen Shrimp sitting on the bottom, could I have fought a baby Yellowfin Tuna for 15 minutes? Brought it in and grabbed it by the tail, it had teeth. It also had serated top and bottom edges to the double sickle tail. Fins were translucent yellow. Couldn't have weighed more than 5-6 lb. Might have been 20' long. Could be wrong, am looking for opinions, sorry, no pics but...yes I turned it loose.